wpa_supplicant: Add initial roaming support

This commit adds different features from 802.11k and 802.11v
specifications to make the device ready for network assisted
roaming. It also adds initial framework for device to detect
whether it needs to move to a better AP.

Followings are added as part of this.

1. Support for sending neighbor report request and provide
   the report back to the APP.
2. Support for beacon measurement report.
3. Support for link measurement report.
4. Support for sending bss transition management query frame
   (triggered by the APP).
5. Support for bss transition management request and move
   to the candidate based on that.
6. Sending the bss transition management response.

components/wpa_supplicant/src/common/scan.h

@@ -0,0 +1,25 @@
+/*
+ * WPA Supplicant - Scanning
+ * Copyright (c) 2003-2014, Jouni Malinen <j@w1.fi>
+ *
+ * This software may be distributed under the terms of the BSD license.
+ * See README for more details.
+ */
+
+#ifndef SCAN_H
+#define SCAN_H
+
+/*
+ * Noise floor values to use when we have signal strength
+ * measurements, but no noise floor measurements. These values were
+ * measured in an office environment with many APs.
+ */
+#define DEFAULT_NOISE_FLOOR_2GHZ (-89)
+
+struct wpa_driver_scan_params;
+void wpa_supplicant_req_scan(struct wpa_supplicant *wpa_s, int sec, int usec);
+int wpa_supplicant_trigger_scan(struct wpa_supplicant *wpa_s,
+				struct wpa_driver_scan_params *params);
+const u8 * wpa_scan_get_ie(const struct wpa_scan_res *res, u8 ie);
+void wpa_scan_free_params(struct wpa_driver_scan_params *params);
+#endif /* SCAN_H */